胜红蓟精油复合微乳液体系构建及其对芦柑保鲜的影响

为更好的资源化利用入侵植物胜红蓟,提高芦柑的保鲜效果,本研究以胜红蓟精油为油相,吐温-80为表面活性剂,乙醇为助表面活性剂,碳酸钠和羧甲基壳聚糖水溶液为水相,采用拟三元相图筛选最优纳米级复合微乳液体系,并检测其在不同浓度(2.5、5.0、10.0和20.0 mg·mL^-1)下对意大利青霉、指状青霉和扩展青霉的抑菌活性和芦柑染菌抑制效果,用最优浓度处理芦柑果实,探究其对芦柑在不同贮藏条件下(25℃和4℃)的保鲜效果。结果表明,最优复合微乳液体系(A₈₀)的配方为胜红蓟精油∶乙醇∶吐温-80∶3%碳酸钠∶0.5%羧甲基壳聚糖=0.13∶0.38∶0.13∶1∶3,其粒径为34.47 nm。复合微乳液体系浓度为20 mg·mL^-1时,对意大利青霉、指状青霉和扩展青霉的抑菌效果最好,抑制率分别为64.86%、60.23%和86.96%,对芦柑的染菌抑制率为76.48%。此浓度复合微乳液A₈₀对4℃贮藏条件的芦柑保鲜效果最好,贮藏30 d后芦柑失重率为22.24%,对照组失重率为26.47%,腐烂率为11.33%,较对照组降低50%。构建的胜红蓟精油复合微乳液体系处理芦柑,不仅可以有效抑菌,延缓芦柑果实水分散失和重量损失,而且能延长芦柑的保鲜期。本研究结果为胜红蓟精油天然保鲜剂的开发和芦柑储藏保鲜提供了一定的理论基础。

Construction of Composite Micro-emulsion System of Ageratum conyzoides L. Essential Oil and Its Effect on Freshness Preservation of Citrus reticulate Blanc Ponkan

To better utilize the invasive plant Ageratum conyzoides L. and improve the freshness preservation of Citrus reticulate Blanc Ponkan, this study screened the optimal nanoscale composite micro-emulsion system based on pseudo-ternary phase diagrams by using A. conyzoides L. essential oil as the oil phase, Tween-80 as the surfactant, ethanol as the cosurfactant, and sodium carbonate and carboxymethyl chitosan solutions as the aqueous phase. Its antimicrobial activities against Penicillium italicum, Penicillium digitatum and Penicillium expansum were assayed at different concentrations (2.5, 5.0, 10.0 and 20.0 mg·mL^-1), as well as its C. reticulate Blanc Ponkan contamination inhibitory effect. The fruits of C. reticulate Blanc Ponkan were treated with optimal concentration of the micro-emulsion system to investigate the freshness preservation effect in different storage conditions (25℃ and 4℃). The results showed that the optimal formulation of the compound micro-emulsion system (A₈₀) was A. conyzoides L. essential oil: ethanol: Tween-80: 3% sodium carbonate: 0.5% carboxymethyl chitosan=0.13∶0.38∶0.13∶1∶3 with particle size of 34.47 nm. At concentration of 20 mg·mL^-1, the micro-emulsion system exhibites the best antimicrobial activities against P. italicum, P. digitatum and P. expansum, with inhibition rates of 64.86%, 60.23% and 86.96%, respectively. Meanwhile, its contamination inhibition rate for living C. reticulate Blanc Ponkan was 76.48%. The compound micro-emulsion A₈₀ at this concentration level had the best preservation effect on C. reticulate Blanc Ponkan stored at 4℃. After 30 d of storage, the weight loss rate of C. reticulate Blanc Ponkan was 22.24%, while the weight loss rate of control group was 26.47%. Besides, the rotting rate was 11.33%, which was 50% lower than the control group. Treatment of C. reticulate Blanc ‘Ponkan’ with the prepared compound micro-emulsion system of A. conyzoides L. essential oil could not only effectively inhibit microbes and delay the dehydration and weight loss, but also prolong its preservation life of citrus fruits. The results could provide certain theoretical basis for the development of A. conyzoides L. essential oil as natural preservative and for the storage, as well was preservation of C. reticulate Blanc Ponkan.